whisker vs hair's-breadth

whisker and hair's-breadth both are nouns.

Word	Noun	Adjective	Verb	Adverb
whisker	Yes	No	Yes	No
hair's-breadth	Yes	No	No	No

As nouns, whisker and hair's-breadth are synonyms defined as:

Other synonyms of whisker include hair, hairsbreadth.

whisker (noun)	hair's-breadth (noun)
a long stiff hair growing from the snout or brow of most mammals as e.g. a cat	a very small distance or space
a very small distance or space

whisker (verb)	hair's-breadth (verb)
furnish with whiskers